DOC: Add external links to TOC

Author: effigies

doc/users/index.rst

@@ -14,9 +14,9 @@
    neurodocker
    caching_tutorial
 
-- `Nipype tutorials <https://miykael.github.io/nipype_tutorial/>`_
-- `Porcupine graphical interface
-  <https://timvanmourik.github.io/Porcupine/getting-started/>`_
+.. toctree::
+   Nipype tutorials <https://miykael.github.io/nipype_tutorial/>
+   Porcupine graphical interface <https://timvanmourik.github.io/Porcupine/getting-started/>
 
 .. toctree::
    :maxdepth: 1